Remove CRWSessionController usage from BrowserViewController.

ios/web/public/navigation_manager.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef IOS_WEB_PUBLIC_NAVIGATION_MANAGER_H_
 #define IOS_WEB_PUBLIC_NAVIGATION_MANAGER_H_
 
 #include <stddef.h>
 
 #import "base/mac/scoped_nsobject.h"
 #include "ios/web/public/browser_url_rewriter.h"
+#include "ios/web/public/navigation_item_list.h"
 #include "ios/web/public/referrer.h"
 #include "ui/base/page_transition_types.h"
 
 @class NSDictionary;
 @class NSData;
 
 namespace web {
 
 class BrowserState;
 class NavigationItem;
@@ skipping 120 matching lines @@
   virtual bool CanGoBack() const = 0;
   virtual bool CanGoForward() const = 0;
   virtual bool CanGoToOffset(int offset) const = 0;
   virtual void GoBack() = 0;
   virtual void GoForward() = 0;
 
   // Navigates to the specified absolute index.
   // TODO(crbug.com/533848): Update to use size_t.
   virtual void GoToIndex(int index) = 0;
 
+  // Returns a list of all non-redirected NavigationItems whose index precedes
+  // or follows the current index.
+  virtual NavigationItemList GetBackwardItems() const = 0;

[Eugene But (OOO till 7-30), 2017/03/10 16:23:27]

Could you please add tests for these.

[kkhorimoto, 2017/03/10 23:02:20]

They already exist in crw_session_controller_unittest.mm.  I'll transfer them
over to NavigationManager unittests once the functionality is actually handled
by that class; currently it's just a pass-through to CRWSessionController.

+  virtual NavigationItemList GetForwardItems() const = 0;
+
   // Reloads the current item. If |check_for_repost| is true and the current
   // item has POST data the user is prompted to see if they really want to
   // reload the page. In nearly all cases pass in true.  If a transient item is
   // showing, initiates a new navigation to its URL.
   virtual void Reload(bool check_for_repost) = 0;
 
+  // Inserts copies of |other_controller|'s NavigationItems to the front of this

[Eugene But (OOO till 7-30), 2017/03/10 16:23:27]

NavigationController does not have this method, so do we need it in navigation
manager? This very method is used for preload feature. Do you know how preload
is implemented on other platforms? CopyStateFromAndPrune could be API we need.

[kkhorimoto, 2017/03/10 23:02:20]

Will do this on the other CL.

+  // session history.
+  virtual void InsertStateFromManager(const NavigationManager* manager) = 0;
+
   // Forces the pending item to be loaded using desktop user agent. Note that
   // the pending item may or may not already exist.
   // TODO(crbug.com/692303): Remove this when overriding the user agent doesn't
   // create a new NavigationItem.
   virtual void OverrideDesktopUserAgentForNextPendingItem() = 0;
 };
 
 }  // namespace web
 
 #endif  // IOS_WEB_PUBLIC_NAVIGATION_MANAGER_H_